Module Overview Functional Description; Control Board - Cardinal Health Alaris GW Technical & Service Manual

Circuit Descriptions
Circuit Descriptions

Module overview functional description

The pump is designed to be serviced generally to major assembly level. The PCBs are designed as non-serviceable items and as such,
can only be replaced as complete parts.
Cardinal Health will make available, on request, circuit diagrams, which will assist appropriately qualified technical personnel to repair
those parts of the pump which are designated by the manufacturer as repairable.
The main circuitry within the Alaris® GW Volumetric Pump is contained on three printed circuits boards - Control PCB, Power Supply
and Communications PCB, and a small Pressure Sensor and Encoder PCB and additional plug in sensors.

Control Board

Microcontroller Block
All control and display functions are controlled by this part. Safety functions are spread around the pump with various parts. The
controller is supported by a watchdog and power reset circuit. An EEPROM is used to store logged data for the pump. There is a
battery backed real-time clock.
Power Control Block
Raw DC power is connected from the Power Supply unit to JP1 connector. In the event of the raw DC exceeding 36 volts, components
form a crowbar. Components form a 12 volt Switch Mode Power Supply (SMPS). Components form a 12-volt monitor circuit for the
Microcontroller. The battery is connected to pin 3 of JP1 and is constantly charged when connected to the mains. Components form
a 5-volt reference voltage to the main processor. A switch mode regulator supplies 5-volts (VCC) to the pump. There are two 5-volt
crowbar protection circuits.
Motor Driver
A Microcontroller I/O is used to control the motor speed. The modulated signal is smoothed to a DC voltage appropriate to control
motor speed. Relay 1 is used to reverse the voltage applied to the motor. This reversal is used for some modes of operation. Safety
devices stop the motor if necessary.
User Interface
Microcontroller drives the seven segment displays and the LEDs. The keyboard is scanned for key depressions .The display currents are
monitored. Time division multiplexing enables complete control of a user interface display and input with the Microcontroller.
Air-in-line sensor
A phase shift oscillator drives the Air-in-Line sensor; the output of the phase shift oscillator signal is fed into a voltage controlled
oscillator. The signal is transmitted through the fluid filled tubing and received by the ultrasonic sensor. The received signal is then
passed through a window detector and then to a level detector and input into the Microcontroller.
Air-in-Line
Two ultrasonic transducers continuously check for the presence of air in the IV infusion set throughout the infusion. This air-in-line
feature operates in two modes:
Single Bubble Detection - The pump will alarm and display Air OCCL whenever a single air bubble greater than the air-in-line volume
alarm limit is detected. The alarm limit can be configured to 50, 100, 250 or 500µl. See also "Configurable Options" section of Chapter 2.
Air-in-Line Accumulation - This accumulation feature monitors the volume of air that passes through the IV infusion set by
accumulating the volume of individual bubbles over a 15 minute window. The accumulation will alarm if more than 500µL of air is
registered. This feature is particularly useful with infusions for patients that are highly sensitive to air (i.e., neonates, paediatrics) or
when infusing products that create significant volumes of small air bubbles.
Flow sensor
The flow sensor is input into the Main Processor.
Door sensor
A Hall effect sensor detects if the door is open or closed and a Microcontroller reads the state of the sensor.
Buzzer
The Microcontroller is used to switch on the alarm (buzzer).
Audio Alarm
The input to the Audio alarm section is driven by a signal from the Microcontroller, fed into a phase shift oscillator and through an RC
network to remove any DC present on the signal. The signal is amplified and drives the speaker.
Alaris® GW Volumetric Pump /77 1000SM00006 Issue 4